i just got off the phone with the good people at folgers
to learn about how concentrated instant coffee is ..
so i can adjust my recipe ..
it turns out that instant is 3x as concentrated ( 1 tsp / cup vs 1 tbs / cup ),
so for a single roll of film, i am guessing
i will be roasting up a half cup to a whole cup of beans ....
the wrench in the spokes is that different varieties of coffee
have different characteristics and different caffic acid contents.
i know i have had different results depending on the brand of coffee i have
used ( "el gringo" vs. "stop and shop generic" ) ... typical instant coffee
is never 100% robusta beans, so who knows what is going to happen
when i use 100% in my mix ...